Data security devices are currently commercially available. These devices use either software or hardware to convert the data to be stored in a hard disk drive in such a manner that only the specific decrypting means of such devices can read the encrypted data. Heretofore, the decrypting means of data security device for both the software type and hardware type encrypting means are in the form of software which takes CPU (central processing unit) time and memory in execution. This worsens the efficiency of the CPU.
It is therefore desirable to have a data security device in the form of hardware so as to provide a desired data security while maintaining the CPU efficiency and the availability of the computer memory and the CPU to the users.